Base station methods and apparatus for establishing connections

ABSTRACT

Methods and apparatus for establishing communication links, used to support communications sessions with one or more end nodes, e.g., mobile devices, are described. Various features are directed to a mobile node controlling the establishment of initial links to a first access node and the establishment of new links from a first access node to a second access node during a handoff operation using highly efficient messages and signal.

FIELD OF THE INVENTION

This invention relates to communications system and, more particularly,to methods and apparatus for establishing connections in wireless, e.g.,cellular, communications networks.

BACKGROUND OF INVENTION

Communications system frequently include a plurality of network nodeswhich are coupled to access nodes through which end nodes, e.g., mobiledevices, are coupled to the network. Network nodes may be arranged in ahierarchy. Access Authentication and Authorization (AAA) servers arenodes which are normally placed relatively high in the networkhierarchy. They normally provide information used for security andaccess control purposes. Access nodes frequently have a secure link withan AAA server in cases where such servers are used. The secure link maybe through one or more nodes in the hierarchy.

Operators typically manage access sessions in IP networks using theRADIUS protocol and associated RADIUS AAA servers. In the future, AAAsystems may be based on new protocols such as DIAMETER. In a systemusing a RADIUS AAA server, when a user attempts to gain access to anoperator network, for the duration of an access session, the localAccess Router normally issues one or more RADIUS Access-Requests to anAuthentication Server to authenticate that user based on its identitysuch as a Network Access Identifier (NAI). The AAA database typicallyhas stored the identities of those users allowed to access its systemalong with the services features they are able to invoke. When the useris successfully authenticated, its access port on the access device isconfigured with policy state commensurate with the user's serviceAuthorization. The service authorization is normally delivered viaRADIUS to the Access Router by the Authorization Server. Whilstauthorized, service usage during an access session is recorded by theAccess Router, and sent as accounting records to an Accounting Serverusing Accounting-Request messages in the RADIUS protocol. The AccountingServer may be part of the AAA server or it may be an independent serverusing the same protocol with the authorization server. If the user isconnected to multiple Access Routers during a single session then themultiple sessions need to be aggregated in the Accounting Servers.

AAA systems are typically used with Mobile IP to manage IP addressallocations (HoAs), to dynamically allocate HAs, to distribute MNprofiles to the Access Router and also to distribute security keys toauthenticate MIP messages and to secure the air-link. The Mobile Node,an end node which is capable of changing its point of networkattachment, typically sends a MIP message to gain access to the system,which triggers a AAA request to authenticate and authorize the MobileNode. The AAA MN profile and security state is then passed from the AAAsystem to the Access Router to control services consumed by the MN.

MNs may change their point of network attachment, e.g., as they movefrom one cell to another cell. This involves changing the MNs point ofattachment from a first access node, e.g., a first router, to a secondaccess node, e.g., a second router. This process is commonly known as ahandoff. As part of a handoff the MN's CoA/CCoA needs to be updated andthen transferred into the HA using MIP signaling so that packets areredirected to the MN via the new Access Router. As part of handoffprocess, it is necessary to transfer at least some of the first accessrouter's state information corresponding to the MN involved in thehandoff to the new access router so that the MN service is notinterrupted. This process is known as State Transfer. State transfer mayinclude, e.g., the transfer of AAA profile state information that waspreviously delivered via RADIUS to the AR, at which the MN accesssession commenced. It also may include, e.g., the transfer of air-linksecurity vectors, MN-NAI, MN IP Address, MN-EUI-64, remaining MIPRegistration Lifetime, MN multicast group membership, admission controlstate, resource reservation state, diff-serv state, SIP session state,compressor state, MN scheduling history and/or many other potentialitems of MN specific AR state information.

In at least one known system, the transfer of state information during ahandoff is accomplished by the new access node to which a mobile node isconnecting sending a state transfer message through the communicationsnetwork to the old access node to which the mobile node was connected.In response the old access node forwards state information to the newaccess node. Alternatively a core node is used to store state associatedwith a given mobile node. When said mobile node attempts to move toanother target access node, said target access node can retrieve stateassociated with said mobile node from said core node.

Mobile IP, (versions 4 and 6) also known as MIPv4 [MIPv4] and MIPv6[MIPv6], enables a mobile node (MN) to register its temporary locationindicated by a care-of address (CoA) to its Home Agent (HA). The HA thenkeeps a mapping (also called a binding) between the MN's permanentaddress, otherwise called Home Address (HoA), and the registered CoA sothat packets for that MN can be redirected to its current location usingIP encapsulation techniques (tunneling). The CoA used by a MN can be anaddress that belongs to a Foreign Agent (FA) in an Access Router whenMIPv4 is used or it can be a temporarily allocated address to the MNitself, from the Access Router prefix, in which case it is called acollocated care-of address (CCoA). The latter model also applies toMIPv4 while it is the only mode of operation in MIPv6. Note that for thepurpose of this document the terms CCoA and CoA as well as Registrationand Binding Update (BU) are interchangeable since they are thecorresponding terms for MIPv4 and MIPv6.

The smallest possible MIPv4 compliant Registration Request messageincludes at least the following headers and fields.

-   -   IP header (at least 160 bits long)    -   UDP header (at least 64 bits long)

The UDP header is followed by the Mobile IP fields shown below: (atleast 192 bits long) 0                   1                   2                   3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+|     Type      |S|B|D|M|G|r|T|x|          Lifetime             |+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+|+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−++−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+|                          Home Address                         |+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+|                           Home Agent                          |+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+|                        Care-of Address                        |+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+|                                                               |+                         Identification                        +|                                                               |+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+| Extensions ... +−+−+−+−+−+−+−+−

Type 1 (Registration Request)

-   -   S Simultaneous bindings. If the ‘S’ bit is set, the mobile node        is requesting that the home agent retain its prior mobility        bindings.    -   B Broadcast datagrams. If the ‘B’ bit is set, the mobile node        requests that the home agent tunnel to it any broadcast        datagrams that it receives on the home network.    -   D Decapsulation by mobile node. If the ‘D’ bit is set, the        mobile node will itself decapsulate datagrams which are sent to        the care-of address. That is, the mobile node is using a        co-located care-of address.    -   M Minimal encapsulation. If the ‘M’ bit is set, the mobile node        requests that its home agent use minimal encapsulation [34] for        datagrams tunneled to the mobile node.    -   G GRE encapsulation. If the ‘G’ bit is set, the mobile node        requests that its home agent use GRE encapsulation [16] for        datagrams tunneled to the mobile node.    -   r Sent as zero; ignored on reception.    -   T Reverse Tunneling requested;    -   x Sent as zero; ignored on reception.

Lifetime

-   -   The number of seconds remaining before the registration is        considered expired. A value of zero indicates a request for        deregistration. A value of 0xffff indicates infinity.

Home Address

-   -   The IP address of the mobile node.

Home Agent

-   -   The IP address of the mobile node's home agent.

Care-of Address

-   -   The IP address for the end of the tunnel.

Identification

-   -   A 64-bit number, constructed by the mobile node, used for        matching Registration Requests with Registration Replies, and        for protecting against replay attacks of registration messages.

Extensions (at least 176 bits long)

-   -   The fixed portion of the Registration Request is followed by one        or more of the Extensions.

An authorization-enabling extension MUST be included in all RegistrationRequests. 0                   1                   2                   3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+|     Type      |     Length    |         SPI  ....+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+       ... SPI (cont.)          |       Authenticator ...+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+

Type

-   -   32

Length

-   -   4 plus the number of bytes in the Authenticator.

SPI

-   -   Security Parameter Index (4 bytes). An opaque identifier.

Authenticator

-   -   The default authentication algorithm uses HMAC-MD5 to compute a        128-bit “message digest” of the registration message.

Authenticator Extension0                   1                   2                   3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+| ∠   Type      |     Length    |         SPI  ....       ... SPI (cont.)     ∠    |       Authenticator ...+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+

Type

-   -   32

Length

-   -   4 plus the number of bytes in the Authenticator.

SPI

-   -   Security Parameter Index (4 bytes). An opaque identifier.

Authenticator

-   -   The default authentication algorithm uses HMAC-MD5 to compute a        128-bit “message digest” of the registration message.

The smallest possible MIPv4 compliant Registration Request message shownabove is 592 bits long which can result in inefficient use of resourceswhen it has to be transmitted over a wireless link for the purpose ofregistration and handoff. Note that in practice typical MIPv4 compliantRegistration Request messages are significantly larger than thecalculated minimum value but said minimum value is used for illustrationpurposes.

The smallest possible MIPv4 compliant Registration response messageincludes at least the following headers and fields.

-   -   IP header (at least 160 bits long)    -   UDP header (at least 64 bits long)

The UDP header is followed by the Mobile IP fields shown below: (atleast 160 bits long) 0                   1                   2                   3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+|     Type      |     Code      |           Lifetime            |+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+|                          Home Address                         |+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+|                           Home Agent                          |+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+|                                                               |+                         Identification                        +|                                                               |+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+| Extensions ... +−+−+−+−+−+−+−+−

Type 3 (Registration Reply)

-   -   Code A value indicating the result of the Registration Request.

Lifetime

-   -   If the Code field indicates that the registration was accepted,        the Lifetime field is set to the number of seconds remaining        before the registration is considered expired. A value of zero        indicates that the mobile node has been deregistered. A value of        0xffff indicates infinity.

Home Address

-   -   The IP address of the mobile node.

Home Agent

-   -   The IP address of the mobile node's home agent.

Identification

-   -   A 64-bit number used for matching Registration Requests with        Registration Replies, and for protecting against replay attacks        of registration messages.

Extensions (at least 176 bits long)

-   -   The fixed portion of the Registration Reply is followed by one        or more of the Extensions.    -   An authorization-enabling extension MUST be included in all        Registration Replies.

Authenticator Extension0                   1                   2                   3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+|     Type      |     Length    |         SPI  ....+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+       ... SPI (cont.)          |       Authenticator ...+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+−+

Type

-   -   32

Length

-   -   4 plus the number of bytes in the Authenticator.

SPI

Security Parameter Index (4 bytes). An opaque identifier.

Authenticator

-   -   The default authentication algorithm uses HMAC-MD5 to compute a        128-bit “message digest” of the registration message.

The smallest possible MIPv4 compliant Registration Response messageshown above is 560 bits long which can result in inefficient use ofresources when it has to be transmitted over a wireless link for thepurpose of registration and handoff. Note that in practice typical MIPv4Registration Response messages are significantly larger than thecalculated minimum value but said minimum value is used for illustrationpurposes.

Also note that as it is well know to persons skilled in the art, thesmallest possible Mobile IPv6 (MIPv6) compliant Binding Updated(equivalent to a MIPv4 Registration Request) is larger than the smallestpossible MIPv4 compliant Registration Request message. Finally note thatas it is well know to persons skilled in the art, the smallest possibleMobile IPv6 (MIPv6) compliant Binding Ack (equivalent to a MIPv4Registration Response) is larger than the smallest possible MIPv4compliant Registration Response message

In view of the above discussion, it should be appreciated that there isa need for new and more efficient methods of implementing theestablishment of network links to access nodes in the case of a mobilenode initial registration with a network, a handoff to a new access nodeor in other cases where a mobile node enters a new cell.

SUMMARY OF THE INVENTION

The present invention is directed to methods and apparatus forestablishing connections between wireless terminals and access nodes.

Various methods and apparatus of the invention can be used to establishcommunication links with one or more mobile nodes. Established links canbe used to support communications sessions with one or more end nodes,e.g., mobile devices.

Various novel features are directed to mobile node methods ofcontrolling the establishment of initial links to a first access node.Other features are directed to the establishment of a new link as partof a mobile node handoff from a first access node to a second accessnode during a handoff operation using highly efficient messages andsignal.

Highly efficient messages, often far shorter than mobile IPv4 or IPv6messages that might be used to perform similar tasks are generated, usedand stored in accordance with various embodiments of the invention.

While some features are directed to wireless terminal methods andapparatus, as well as to novel messages of the invention stored in awireless terminal, other features are directed to novel access nodemethods and apparatus.

The invention is also directed to data storage devices, e.g., memorydevices, which store one or more of the novel messages of the presentinvention.

Additional features and benefits of the present invention are discussedin the detailed description which follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a network diagram of an exemplary communicationssystem implemented in accordance with the present invention.

FIG. 2 illustrates an exemplary end node implemented in accordance withthe present invention.

FIG. 3 illustrates an exemplary access node implemented in accordancewith the present invention.

FIG. 4 illustrates an exemplary Server Node implemented in accordancewith the present invention.

FIG. 5 illustrates an exemplary Home Agent node implemented inaccordance with the present invention.

FIG. 6 illustrates an exemplary reduced size IP registration messageimplemented according to this invention.

FIG. 7 illustrates an exemplary reduced size IP registration responsemessage implemented according to this invention.

FIG. 8 illustrates exemplary signaling performed in accordance with thepresent invention when an end node transitions from one access node toanother access node.

DETAILED DESCRIPTION

The methods and apparatus of the present invention for establishing linkand network connections to access nodes used to support communicationssessions with one or more end nodes, e.g., mobile devices, can be usedwith a wide range of communications systems. For example the inventioncan be used with systems which support mobile communications devicessuch as notebook computers equipped with modems, PDAs, and a widevariety of other devices which support wireless interfaces in theinterests of device mobility.

FIG. 1 illustrates an exemplary communication system 100 implemented inaccordance with the present invention, e.g., a cellular communicationnetwork, which comprises a plurality of nodes interconnected bycommunications links. Nodes in the exemplary communication system 100exchange information using signals, e.g., messages, based oncommunication protocols, e.g., the Internet Protocol (IP). Thecommunications links of the system 100 may be implemented, for example,using wires, fiber optic cables, and/or wireless communicationstechniques. The exemplary communication system 100 includes a pluralityof end nodes 144, 146, 144′, 146′, 144″, 146″, which access thecommunication system via a plurality of access nodes 140, 140′, 140″.The end nodes 144, 146, 144′, 146′, 144″, 146″ may be, e.g., wirelesscommunication devices or terminals, and the access nodes 140, 140′, 140″may be, e.g., wireless access routers or base stations. The exemplarycommunication system 100 also includes a number of other nodes 104, 106,109, 110, and 112, used to provide interconnectivity or to providespecific services or functions. Specifically, the exemplarycommunication system 100 includes a Server 104, used to support transferand storage of state pertaining to end nodes. The Server node 104 may bean AAA server, or it may be a Context Transfer Server, or it may be aserver including both AAA server functionality and Context Transferserver functionality.

The FIG. 1 exemplary system 100 depicts a network 102 that includes theServer 104, the Home Agent node 109 and the node 106, all of which areconnected to an intermediate network node 110 by a corresponding networklink 105, 108 and 107, respectively. The intermediate network node 110in the network 102 also provides interconnectivity to network nodes thatare external from the perspective of the network 102 via network link111. Network link 111 is connected to another intermediate network node112, which provides further connectivity to a plurality of access nodes140, 140′, 140″ via network links 141, 141′, 141″, respectively.

Each access node 140, 140′, 140″ is depicted as providing connectivityto a plurality of N end nodes (144, 146), (144′, 146′), (144″, 146″),respectively, via corresponding access links (145, 147), (145∝, 147′),(145″, 147″), respectively. In the exemplary communication system 100,each access node 140, 140′, 140″ is depicted as using wirelesstechnology, e.g., wireless access links, to provide access. A radiocoverage area, e.g., communications cell, 148, 148′, 148″ of each accessnode 140, 140′, 140″, respectively, is illustrated as a circlesurrounding the corresponding access node.

The exemplary communication system 100 is subsequently used as a basisfor the description of various embodiments of the invention. Alternativeembodiments of the invention include various network topologies, wherethe number and type of network nodes, the number and type of accessnodes, the number and type of end nodes, the number and type of Serversand Home or other Agents, the number and type of links, and theinterconnectivity between nodes may differ from that of the exemplarycommunication system 100 depicted in FIG. 1.

In various embodiments of the present invention some of the functionalentities depicted in FIG. 1 may be omitted or combined. The location orplacement of these functional entities in the network may also bevaried.

FIG. 2 provides a detailed illustration of an exemplary end node 200,e.g., a mobile node, implemented in accordance with the presentinvention. The exemplary end node 200, depicted in FIG. 2, is a detailedrepresentation of an apparatus that may be used as any one of the endnodes 144, 146, 144′, 146′, 144″, 146″, depicted in FIG. 1. In the

FIG. 2 embodiment, the end node 200 includes a processor 204, a wirelesscommunication interface 230, a user input/output interface 240 andmemory 210 coupled together by bus 206. Accordingly, via bus 206 thevarious components of the end node 200 can exchange information, signalsand data. The components 204, 206, 210, 230, 240 of the end node 200 arelocated inside a housing 202.

The wireless communication interface 230 provides a mechanism by whichthe internal components of the end node 200 can send and receive signalsto/from external devices and network nodes, e.g., access nodes. Thewireless communication interface 230 includes, e.g., a receiver circuit232 with a corresponding receiving antenna 236 and a transmitter circuit234 with a corresponding transmitting antenna 238 used for coupling theend node 200 to other network nodes, e.g., via wireless communicationschannels.

The exemplary end node 200 also includes a user input device 242, e.g.,keypad, and a user output device 244, e.g., display, which are coupledto bus 206 via the user input/output interface 240. Thus, userinput/output devices 242, 244 can exchange information, signals and datawith other components of the end node 200 via user input/outputinterface 240 and bus 206. The user input/output interface 240 andassociated devices 242, 244 provide a mechanism by which a user canoperate the end node 200 to accomplish various tasks. In particular, theuser input device 242 and user output device 244 provide thefunctionality that allows a user to control the end node 200 andapplications, e.g., modules, programs, routines and/or functions, thatexecute in the memory 210 of the end node 200.

The processor 204 under control of various modules, e.g., routines,included in memory 210 controls operation of the end node 200 to performvarious signaling and processing as discussed below. The modulesincluded in memory 210 are executed on startup or as called by othermodules. Modules may exchange data, information, and signals whenexecuted. Modules may also share data and information when executed. Inthe FIG. 2 embodiment, the memory 210 of end node 200 of the presentinvention includes a signaling/control module 212 and signaling/controldata 214.

The signaling/control module 212 controls signal generation andprocessing relating to receiving and sending signals, e.g., messages,for management of state information storage, retrieval, and processing.Messages stored in memory 210 include a connection request message 610,a connection response message 660, an IP registration message 800 and anIP registration response message 900. Messages 800 and 900 may bereduced, e.g., small size, messages of the invention which are smallerthan convention Mobile IP v4 and/or v6 messages. The messages stored inmemory may be messages which are generated and/or received. The messageswill be discussed in more detail below. Signaling/control data 214includes state information, e.g., parameters, status and/or otherinformation relating to operation of the end node. In particular, thesignaling/control data 214 may include configuration information 216,e.g., end node identification information, and operational information218, e.g., information about current processing state, status of pendingresponses, etc. The module 212 may access and/or modify the data 214,e.g., update the configuration information 216 and/or the operationalinformation 218.

FIG. 3 provides a detailed illustration of an exemplary access node 300implemented in accordance with the present invention. The exemplaryaccess node 300, depicted in FIG. 3, is a detailed representation of anapparatus that may be used as any one of the access nodes 140, 140′,140″ depicted in FIG. 1. In the FIG. 3 embodiment, the access node 300includes a processor 304, memory 310, a network/internetwork interface320 and a wireless communication interface 330, coupled together by bus306. Accordingly, via bus 306 the various components of the access node300 can exchange information, signals and data. The components 304, 306,310, 320, 330 of the access node 300 are located inside a housing 302.

The network/internetwork interface 320 provides a mechanism by which theinternal components of the access node 300 can send and receive signalsto/from external devices and network nodes. The network/internetworkinterface 320 includes, a receiver circuit 322 and a transmitter circuit324 used for coupling the node 300 to other network nodes, e.g., viacopper wires or fiber optic lines. The wireless communication interface330 also provides a mechanism by which the internal components of theaccess node 300 can send and receive signals to/from external devicesand network nodes, e.g., end nodes. The wireless communication interface330 includes, e.g., a receiver circuit 332 with a correspondingreceiving antenna 336 and a transmitter circuit 334 with a correspondingtransmitting antenna 338. The interface 330 is used for coupling theaccess node 300 to other network nodes, e.g., via wireless communicationchannels.

The processor 304 under control of various modules, e.g., routines,included in memory 310 controls operation of the access node 300 toperform various signaling and processing. The modules included in memory310 are executed on startup or as called by other modules that may bepresent in memory 310. Modules may exchange data, information, andsignals when executed. Modules may also share data and information whenexecuted. In the FIG. 3 embodiment, the memory 310 of the access node300 of the present invention includes a State Management module 312 anda Signaling/Control module 314. Corresponding to each of these modules,memory 310 also includes State Management data 313 and theSignaling/Control data 315. Messages stored in memory 310 include aconnection request message 610, a connection response message 660, an IPregistration message 800 and an IP registration response message 900.Messages 800 and 900 may be reduced, e.g., small size, messages of theinvention which are smaller than convention Mobile IP v4 and/or v6messages. Memory 310 also includes a Mobile IPv4 and/or Mobile IPv6registration message 680. The messages stored in memory may be messageswhich are generated and/or received. The messages will be discussed inmore detail below.

The State Management Module 312 controls the processing of receivedsignals from end nodes or other network nodes regarding state storageand retrieval. The State Management Data 313 includes, e.g., end-noderelated information such as the state or part of the state, or thelocation of the current end node state if stored in some other networknode. The State Management module 312 may access and/or modify the StateManagement data 313.

The Signaling/Control module 314 controls the processing of signalsto/from end nodes over the wireless communication interface 330, andto/from other network nodes over the network/internetwork interface 320,as necessary for other operations such as basic wireless function,network management, etc. The Signaling/Control data 315 includes, e.g.,end-node related data regarding wireless channel assignment for basicoperation, and other network-related data such as the address ofsupport/management servers, configuration information for basic networkcommunications. The Signaling/Control module 314 may access and/ormodify the Signaling/Control data 315.

FIG. 4 provides a detailed illustration of an exemplary Server node 400implemented in accordance with the present invention. The exemplaryServer node 400, depicted in FIG. 4, is a detailed representation of anapparatus that may be used as the Server 104 depicted in FIG. 1. In theFIG. 4 embodiment, the Server node 400 includes a processor 404, memory410, a network/internetwork interface 420, coupled together by bus 406.Accordingly, via bus 406 the various components of the access node 400can exchange information, signals and data. The components 404, 406,410, 420 of the access node 400 are located inside a housing 402.

The network/internetwork interface 420 provides a mechanism by which theinternal components of the Server node 400 can send and receive signalsto/from external devices and network nodes. The network/internetworkinterface 420 includes, a receiver circuit 422 and a transmitter circuit424 used for coupling the node 400 to other network nodes, e.g., viacopper wires or fiber optic lines.

The processor 404 under control of various modules, e.g., routines,included in memory 410 controls operation of the Server 400 to performvarious signaling and processing. The module included in memory 410 areexecuted on startup or as called by other modules that may be present inmemory 410. In the FIG. 4 embodiment, the memory 410 of the Server 400of the present invention includes a Core State Management module 412 andCore State Management data 413, and a AAA module 415.

The Core State Management Module 412 controls the processing of receivedsignals from other Servers, access nodes, or network nodes regardingstate storage and retrieval. The Core State Management Data 413includes, e.g., end-node state information. The Core State Managementmodule 412 may access and/or modify the Core State Management data 413.

The AAA module 415 performs operation pertaining to authentication,authorization, and accounting.

FIG. 5 illustrates an exemplary Home Agent node 500 implemented inaccordance with the present invention. Exemplary Home Agent node 500 canbe used in the system of FIG. 1, e.g., as home agent node 109 whichserves as a Home Agent. In the FIG. 5 embodiment, the home agent node500 includes an input/output interface 501, a processor 503 and memory507, coupled together by bus 502. The elements 501, 502, 503 and 507 ofhome agent node 500 are located inside a housing 508, e.g., a case ofplastic and/or metal, represented by the rectangle surrounding thenode's internal elements 501, 502, 503 and 507. Accordingly, via bus 502the various components of the access node 500 can exchange information,signals and data. The input/output interface 501 includes circuitry usedfor coupling the node 500 to other network nodes, e.g., via fiber opticlines, and potentially to end nodes, e.g., via wireless communicationschannels.

The processor 503 under control of various modules, e.g., routines,included in memory 507 controls operation of the home agent node 500 toperform various signaling, routing and other operations as will bediscussed below. The modules included in memory 507 are executed onstartup or as called by other modules. Modules may exchange data,information, and signals when executed. Modules may also share data andinformation when executed. In the FIG. 5 embodiment, the memory 507 ofhome agent node 500 of the present invention includes a mobility agentmodule 506 which includes, e.g., parameters, communication sessionand/or end node status information, security information, and/or otherinformation relating to end node interaction and/or communication withan access node and/or another device. Mobility Agent module 506 alsoincludes end node specific state including mappings between end node'shome addresses and care-of addresses.

The mobility agent module 506 allows the node 500 to support end nodemobility and connectivity management services. Thus, the home agent node500 is capable of providing node mobility, session establishment, andsession maintenance services to connected end nodes. The mobility agentmodule 506 may be implemented in a plurality of ways. In the FIG. 5embodiment it is implemented with a collection of sub-modules. Asillustrated, the mobility agent module 506 includes Mobile IPv4sub-module 505 and Mobile IPv6 sub-module 504. By including sub-modules505 and 504, the mobility agent module 506 is capable of supportingmultiple versions of Mobile IP signaling including Mobile IPv4 andMobile IPv6 signaling. In various embodiments, the mobility agent module506 includes a subset of the sub-modules 505 and 504 shown in FIG. 5.For example, in embodiments where Mobile IPv6 is not required, theMobile IPv6 Home Agent sub-module 504 may be omitted.

FIG. 6 illustrates an exemplary reduced size IP registration message 800implemented according to this invention. Said message 800, althoughsufficient for the purposes of setting up network layer connectivity andredirecting Mobile IP tunnels, as shown in the invention, is of smallersize than even the smallest possible Mobile IPv4 compliant RegistrationRequest message shown in the background section. Exemplary reduced sizeIP registration message 800 includes: a Message Type field 810, areserved field 820, a “D” (Deregistration) field 830, an “I” (Initial)field 840, a Message Identifier 850, and zero or more optionalExtensions 860.

Message Type field 810 includes a value which identifies said message asa reduced size IP registration message. In some embodiment of thisinvention, message type field value identifies the message as a MobilityManagement Protocol message referred to as L3RegistrationRequestmessage.

Reserved field 820 is reserved for future use. In one embodiment of thisinvention the value of reserved field 820 is set to zero by the senderand is ignored by the receiver.

“D” (Deregistration) field 830 includes a value which indicates whetherthis message is sent to register a network layer or to deregister from apreviously registered network layer.

“I” (Initial) field 840 includes a value which indicates whether thismessage is the initial registration message for this network layer or asubsequent registration for a network layer that was establishedearlier.

Message Identifier 850 includes a value which distinguishes the message800 from at least another message of the same type (message 800) sentprior to this one. In some exemplary embodiments of this invention theMessage Identifier field 850 takes the values of a monotonicallyincreasing sequence number. In other exemplary embodiments of thisinvention said Message Identifier field 850 takes the values of atimestamp. In still other exemplary embodiments of this invention saidMessage Identifier field 850 is comprised partly by a sequence numberand partly by a timestamp.

Zero or more optional Extensions 860 may be included that may includevarious additional parameters. In some exemplary embodiments of thisinvention such extensions include the target access node Identifierextension 870, which identifies the access node that message 800 is sentto (e.g., target access node 530 in FIG. 8), the last access nodeidentifier extension 880, which identifies the access node that the endnode sending message 800 (e.g., end node 510 in FIG. 8) was lastconnected at the network layer with (e.g., access node 520 in FIG. 8)and an authenticator extension 890 authenticating message 800. In someexemplary embodiments of the invention each of said extensions 870 and880 includes at least a Type field, the value of which identifies thetype of the extension, a length field, the value of which identifies thelength of the extension and an Identifier field, the value of whichidentifies one of target access node and last access node. In some suchembodiments of the invention the authenticator extension 890 includes atleast a Type field, the value of which identifies the type of theextension, a length field, the value of which identifies the length ofthe extension and an authenticator field, the value of whichauthenticates the message cryptographically; said authentication fieldvalue calculated based on a key shared between the sender and thereceiver. In some exemplary embodiments of this invention, the lastaccess node identifier extension 880 is not included when the value ofthe “I” filed 840 indicates that message 800 is an initial registration,while the last access node identifier extension 880 is included when thevalue of the “I” filed 840 indicates that message 800 is not an initialregistration. In some embodiments of this invention the authenticatorextension 890 is an optional extension so it may be omitted from message800. Various combinations of optional extensions are possible, inaccordance with various embodiments of the invention including zero, onetwo or three extensions 890.

In an exemplary embodiment of this invention, Message Type field 810 is8 bits long, reserved field 820 is 14 bits long, “D” field 830 is a 1bit long flag, “I” field 840 is a 1 bit long flag, Message Identifier850 is comprised of a 16 bit sequence number and a 32 bit timestamp. Inthe same embodiment of this invention, when the optional extensions,target access node identifier 870 and last access node identifier 880,are included in the message 800, each is comprised of a 8 bit typefield, 8 bit length field and at most 64 bit Identifier. In the sameembodiment of this invention, when the optional authenticator extension890 is included in the message 800, it comprises a 8 bit type file, 8bit length field and at most 64 bit authenticator. In the sameembodiment of this invention the maximum length of a reduced size IPregistration message 800 is 312 bits which is significantly smaller thanthe smallest possible MIPv4 compliant Registration Request message whichin the background section is shown to be 592 bits long.

FIG. 7 illustrates an exemplary reduced size IP registration responsemessage 900 implemented according to this invention. Said message 900,although sufficient for the purposes of setting up network layerconnectivity and redirecting Mobile IP tunnels, as shown in theinvention, is of smaller size than even the smallest possible MobileIPv4 Registration response message shown in the background section.Exemplary reduced size IP registration response message 900 includes: aMessage Type field 910, a Message Identifier field 920, a Response Codefield 930, a Reserved field 940, a Lifetime field 950, and zero or moreoptional Extensions 960.

Message Type field 910 includes a value which identifies said message asa reduced size IP registration response message. In some embodiments ofthis invention the Message type field value identifies the IPRegistration Response Message 900 as a Mobility Management Protocolmessage referred to as L3RegistrationResponse message.

Message Identifier 920, includes a value which matches message 900 witha corresponding reduced size IP registration message 800. In someembodiments of this invention the Message Identifier field 920 takes thevalues from at least part of the value of the Message Identifier field850 of the corresponding reduced size IP registration message 800, saidmessage 900 is in response to Response Code field 930 includes a valuewhich indicates the success or failure of the IP registration operation.

Reserved field 940 is reserved for future use. In some embodiment ofthis invention the value of this reserved field 940 is set to zero bythe sender and is ignored by the receiver.

Lifetime field 950 includes a value which indicates the lifetime of theIP registration. In some embodiments of this invention the value of thelifetime field 950 corresponds to the lifetime of an IP addressassociated with the receiver of message 900. In some such embodiments ofthis invention the receiver of message 900 should send another reducedsize IP registration message before the value of the Lifetime field 950expires following reception of message 900.

Zero or more optional Extensions 960 may be included that may includevarious additional parameters. In some embodiments of this inventionsuch extensions include Home address extension 970, which is an IPaddress associated with the receiver of message 900 (e.g., the IPaddress of end node 510 in FIG. 8), the Home Agent Address extension980, which identifies the address of the Mobile IP Home Agent servingthe Home Address included in extension 970. and an authenticatorextension 990 authenticating message 900. In some exemplary embodimentsof the invention each of said extensions 970 and 980 includes at least aType field, the value of which identifies the type of the extension, alength field, the value of which identifies the length of the extensionand an address field, the value of which represents an IP address. Insome such embodiments of the invention the authenticator extension 990includes at least a Type field, the value of which identifies the typeof the extension, a length field, the value of which identifies thelength of the extension and an authenticator field, the value of whichauthenticates the message cryptographically; said authentication fieldvalue calculated based on a key shared between the sender and thereceiver. In some exemplary embodiments of this invention, the homeaddress extension 970 and home agent address extension 980 are onlyincluded when the value of the “I” filed 840 in the correspondingreduced size IP registration message 800, message 900 is in response to,indicates an initial registration, while the home address extension 970and home agent address extension 980 are not included when the value ofthe “I” filed 840 in the corresponding reduced size IP registrationmessage 800, message 900 is in response to, indicates a subsequentregistration. Various combinations of optional extensions are possiblein accordance with various embodiments of the invention including zero,one two or three of extensions 970, 980, 990.

In an exemplary embodiment of this invention, Message Type field 910 is8 bits long, Message Identifier 920 is comprised of a 16 bit sequencenumber, Response code field 930 is 8 bits long, Reserved field 940 is 8bits long and Lifetime field 950 is 16 bits long. In the same embodimentof this invention, when the optional extensions home address 970 andhome agent address 980 are included in the message 900, each iscomprised of a 8 bit type field, 8 bit length field and at most 32 bitsIP address. In the same embodiment of this extension, when the optionalauthenticator extension 990 is included in the message 900, it comprisesa 8 bit type file, 8 bit length field and at most 64 bit authenticator.In the same embodiment of this invention the maximum length of a reducedsize IP registration response message 900 is 232 bits which issignificantly smaller than the smallest possible MIPv4 compliantRegistration response message which in the background section is shownto be 560 bits long.

FIG. 8 illustrates exemplary signaling performed in accordance withexemplary embodiments of the invention. The signaling is illustrated inthe context of exemplary system 100 illustrated in FIG. 1. The End Node510 corresponds to any of the end nodes 144, 146, 144′, 146′, 144″, 146″of the exemplary system 100 and is implemented according to exemplaryend node implementation 200 of FIG. 2; Access Node 520 and Target AccessNode 530 are simplified implementations of the exemplary access node 300of FIG. 3 and correspond to any of the access nodes 140, 140′, 140″ inthe exemplary system 100 of FIG. 1. The Server 540 is a simplifiedimplementation of Server 400 in FIG. 4 and corresponds to Server 104 inthe exemplary system 100 in FIG. 1. The Home Agent Node 550 is asimplified representation of home agent 500 in FIG. 5 and corresponds tohome agent node 109 in exemplary system 100 in FIG. 1.

In FIG. 8 vertical solid lines 511, 521, 531, 541 and 551 representnodes 510, 520, 530, 540 and 550 in time where the parts of lines 511,521, 531, 541 and 551 at the top of FIG. 8 represent earlier time thanthe parts of said lines at the bottom of FIG. 8. Solid horizontal lines610, 620, 640, 660, 670, 680, 690, 700, 710 and 720 represent signalsbetween nodes 510, 520, 530, 540 and 550. Wide double arrow lines 600,630 and 650 represent groups of signals exchanged between nodes 510,520, 530, 540 and 550. Dashed lines 621 and 641 represent alternativesignals to signals 620 and 640. Dotted lines 630 and 650 representoptional signals. A signal is transmitted between two nodes if the linerepresenting such signal or group of signals indicates a dot at thevertical line representing said node in time. For example signal 610 istransmitted at time 610 a by end node 510 and is received by targetaccess node 530 at time 610 c.

Physical Layer establishment will now be described. In FIG. 8 the endnode 510, at point 600 a transmits a signal, part of the group ofsignals 600, to target access node 530 requesting physical layer accessto said node 530. Target access node 530 receives the signal, part ofgroup of signals 600, at point 600 c and transmits another signal, partof group of signals 600, to end node 510, granting physical layer accessto end node 510.

Link Layer establishment will now be described. End node 510 at point610 a transmits Connections Request message 610 to target access node530, requesting the establishment of link and media access control layercommunications with target access node 530. In some exemplaryembodiments of the invention the Connection Request message 610 includesa first identifier, identifying end node 510. In some embodiments ofthis invention said message 610 also includes a second identifier,identifying the access node that the end node 510 had previouslyestablished a connection with, e.g., access node 520. Said target accessnode 530 receives Connection Request message 610 at point 610 c at whichtime the parameters (e.g., identifiers) included in said message 610 arestored in the memory of target access node 530. In other exemplaryembodiments of this invention message 610 is a Handoff Request messageindicating that end node 510 had earlier established communications withthis or another access node (e.g., access node 520)

An exemplary Core Context Transfer embodiment will be described. Atpoint 620 c said node 530 transmits State Request message 620 to server540, requesting authorization and other state corresponding to end node530. State Request message 620 includes at least some of the parametersstored at point 610 c in the memory of node 530; e.g., the identifier ofend node 510. Server 540 receives State Request message 620 at point 620d and searches its memory for state associated with end node 510. Insome exemplary embodiments of the invention where server 540 is a corestate transfer server, said server 540 transmits state response message640 at point 640 d including authorization state and other state (e.g.,security keys, IP addresses and other parameters) associated with endnode 510. Target node 530 receives said message 640 at point 640 c andstores in its memory at least part of the state associated with end node510 that is included in message 640.

An AAA server embodiment will be described. In some other exemplaryembodiments of this invention where server 540 is an authentication andauthorization (AAA) server, server 540 transmits a message, part of anoptional group of messages 630, at point 630 d, requesting proof for theidentity of end node 510. Said node 510 receives message, part of groupof messages 630, at point 630 a and transmit proof of identity message,part of group of messages 630, to Server 540. In some embodiments ofthis invention server 540 and end node 510 exchange additional messagesthat prove the identity of both end node 510 and server 540 to eachother. When server 540 is satisfied with the identity of end node 510 atpoint 640 d it sends message 640 including authorization state and otherstate (e.g., security keys, IP addresses and other parameters)associated with end node 510. Target access node 530 receives saidmessage 640 at point 640 c and stores in its memory at least part of thestate associated with end node 510 that is included in message 640.

An exemplary Peer-to-Peer Context Transfer embodiment will be described.In some exemplary embodiments of the invention instead of message 620the target access node 530 sends message 621, at point 621 c, to accessnode 520; said access node 520 being the last access node that end node510 had a connection with. Said message 621, according to thisinvention, including at least some of the parameters stored at point 610c in the memory of node 530; e.g., the identifier of end node 510.Access node 520 receives message 621 at point 621 b and searches itsmemory for state associated with end node 510. Said access node 520transmits response message 641 at point 641 b including authorizationstate and other state (e.g., security keys, IP addresses and otherparameters) associated with end node 510. Target node 530 receives saidmessage 641 at point 641 c and stores in its memory at least part of thestate associated with end node 510 that is included in message 641.

An optional security association phase, used in some embodiments of thepresent invention, will now be described. In some embodiments of thisinvention where encryption of data traffic is required over the linkbetween end node 510 and target access node 530, said node 530 transmitsa message, part of an optional group of messages 650, at point 650 c, toestablish at least an encryption key with end node 510. Said node 510receives message, part of group of messages 650, at point 650 a andtransmits key establishment message, part of group of messages 650, totarget access node 530. In some embodiments of this invention targetaccess node 530 and end node 510 exchange additional messages toestablish the encryption key.

Completion of Link Layer establishment will now be described. Targetaccess node 530, at point 660 c, sends Connection Response message 660,granting at least link layer access to end node 510. End node 510receives said message 660 at point 660 a. In the embodiment of thisinvention where message 610 is a Handoff request message, message 660 isa Handoff Response message.

Network Layer establishment will now be described. End node 510constructs in its memory and transmits reduced size IP registrationmessage 670, at point 670 a, to target access node 530 requestingnetwork layer establishment with and packet redirection via said node530. In some exemplary embodiments of the invention, said reduced sizeIP registration message 670 is implemented in accordance with theinvention according to message type 800 of FIG. 6. Target access node530 receives message 670 at point 670 c and stores the values of atleast some of the fields included in said message 670 in its memory.Target access node 530 constructs Mobile IP registration message 680 andtransmits it at point 680 c to home agent 550. According to thisinvention the Identification field of the Mobile IP registration requestmessage 680 include at least a part of the Message Identifier field 850of message 800 of FIG. 6.

An initial registration embodiment will now be described. In oneexemplary embodiment of this invention, reduced size IP registrationmessage 670 implemented according to message 800 in FIG. 6, the “I”field 840 indicates initial registration. In this embodiment of theinvention target access node 530 constructs Mobile IP registrationmessage 680 and transmits it at point 680 c to home agent 550. For theconstruction of Mobile IP Registration Request message 680, targetaccess node 530 combines state associated with end node 510 with statereceived at point 640 c from server 540. In one embodiment of thisinvention where the server 540 is a AAA server, the state associate withend node 510 that is stored at node 530 includes a home address and homeagent address values associated with end node 510, said home address andhome agent address values being allowed to be equal to zero. In oneembodiment of this invention the home agent address included in saidstored state is not equal to zero and target access node 530 uses saidvalue as part of the corresponding field of the Mobile IP registrationrequest message 680. In another embodiment of this invention the homeagent address included in said stored state is equal to zero and targetaccess node 530 uses a locally configured home agent address value aspart of the corresponding field of the Mobile IP registration requestmessage 680. In another embodiment of this invention the home addressincluded in said stored state is not equal to zero and target accessnode 530 uses said value as part of the corresponding field of theMobile IP registration request message 680. In an additional embodimentof this invention the home address included in said stored state isequal to zero and target access node 530 uses the zero value as part ofthe corresponding field of the Mobile IP registration request message680.

Home Agent 550 constructs and transmits registration response message710 at point 710 e to grant the registration request received earlier.Target access node 530 receives registration response message 710 atpoint 710 c and stores at least part of the values included in thefields of message 710 in its memory. Said node 530 constructs in memoryand transmits at point 720 c reduced size IP registration message 720 togrant the network layer registration request to end node 530. In thisexemplary embodiment of this invention, said reduced size IPregistration response message 720 is implemented according to messagetype 900 of FIG. 7. In this embodiment of the invention, the MessageIdentifier field 920 of message 900 in FIG. 7 is copied from thecorresponding Message Identifier included in the Message Identifierfield 850 of message 800 in FIG. 6 this message transmitted in responseto, the home address value included in message 710 from home agent 550is used as part of the value of the home address extension 970 ofmessage 900 in FIG. 7, the Lifetime value included in said message 710is used as the upper limit for the value of the Lifetime field 950 ofmessage 900 in FIG. 7, and the Home Agent Address value included in saidmessage 710 is used part of the value of Home Agent Address extension980 of message 900 in FIG. 7.

A subsequent registration embodiment will now be described. In oneexemplary embodiment of this invention, reduced size IP registrationmessage 670 implemented according to message 800 in FIG. 6, the “I”field 840 indicates a non-initial registration. According to oneembodiment of the invention as discussed in FIG. 6, in a non-initialregistration message 800 the last access node identifier extension 880is included in said message 800. According to this invention said lastaccess node identifier is set to an identifier that identifies accessnode 520.

In this embodiment of the invention target access node 530 constructsMobile IP registration message 680 and transmits it at point 680 c tohome agent 550. For the construction of Mobile IP Registration Requestmessage 680, target access node 530 combines state associated with endnode 510 with state received at point 640 c from server 540. In oneembodiment of this extension where the server 540 is a Core ContextTransfer server, the state associated with end node 510 that is storedat node 530 includes a home address and home agent address valuesassociated with end node 510. In one embodiment of this invention targetaccess node 530 uses said home address and home agent address values aspart of the corresponding field of the Mobile IP registration requestmessage 680.

Target access node 530 also constructs a Mobile IP registration message690 and transmits it at point 690 c to access node 520, which isidentified in the last access node identifier extension of message 670.Access Node 520 receives message 690 at point 690 b and transmits aresponse message 700 at point 700 b. Target access node 530 receivessaid message 700 at point 700 c. In another embodiment of this inventionmessages 690 and 700 are binding update messages while in anotherembodiment of this invention there are other packet redirect messages.According to this invention message 690 identifies at least the end node510. In one embodiment of this invention said identifier being the IPaddress (Home address) of end node 510.

Home Agent 550 constructs and transmits registration response message710 at point 710 e to grant the registration request received earlier.Target access node 530 receives registration response message 710 atpoint 710 c and stores at least part of the values included in thefields of message 710 in its memory. Said node 530 constructs in memoryand transmits at point 720 c reduced size IP registration responsemessage 720 to grant the network layer registration request to end node510. In the exemplary embodiment of this invention, said reduced size IPregistration response message 720 is implemented according to messagetype 900 of FIG. 7. In this embodiment of the invention, the MessageIdentifier field 920 of message 900 in FIG. 7 is copied from thecorresponding Message Identifier included in the Message Identifierfield 850 of message 800 in FIG. 6 that this message 720 is beingtransmitted in response to and the Lifetime value included in saidmessage 710 is used as the upper limit for the value of the Lifetimefield 950 of message 900 in FIG. 7. In this embodiment of the inventionthe home address and home agent address extensions 970 and 980 of FIG. 7are not included in message 720.

In one exemplary embodiment of this invention, end node 510 communicateswith target access node 530 as shown in FIG. 8, while end node 510 hasno other physical, link or network layer connection established with thesame or different access node. In another exemplary embodiment of thisinvention, end node 510 communicates with target access node 530 asshown in FIG. 8, while end node 510 has at least one more physical, linkor network layer connection established with the same or differentaccess node e.g., access node 520.

In various embodiments nodes described herein are implemented using oneor more modules to perform the steps corresponding to one or moremethods of the present invention, for example, signal processing,message generation and/or transmission steps. Thus, in some embodimentsvarious features of the present invention are implemented using modules.Such modules may be implemented using software, hardware or acombination of software and hardware. Many of the above describedmethods or method steps can be implemented using machine executableinstructions, such as software, included in a machine readable mediumsuch as a memory device, e.g., RAM, floppy disk, etc. to control amachine, e.g., general purpose computer with or without additionalhardware, to implement all or portions of the above described methods,e.g., in one or more nodes. Accordingly, among other things, the presentinvention is directed to a machine-readable medium including machineexecutable instructions for causing a machine, e.g., processor andassociated hardware, to perform one or more of the steps of theabove-described method(s).

Numerous additional variations on the methods and apparatus of thepresent invention described above will be apparent to those skilled inthe art in view of the above description of the invention. Suchvariations are to be considered within the scope of the invention. Themethods and apparatus of the present invention may be, and in variousembodiments are, used with CDMA, orthogonal frequency divisionmultiplexing (OFDM), or various other types of communications techniqueswhich may be used to provide wireless communications links betweenaccess nodes and mobile nodes. In some embodiments the access nodes areimplemented as base stations which establish communications links withmobile nodes using OFDM and/or CDMA. In various embodiments the mobilenodes are implemented as notebook computers, personal data assistants(PDAs), or other portable devices including receiver/transmittercircuits and logic and/or routines, for implementing the methods of thepresent invention.

1. A method of operating a base station, the method comprising:receiving a reduced size Mobile IP registration message; and generatingfrom said reduced size Mobile IP registration message at least one of aMobile IPv4 or Mobile IPv6 registration message.
 2. The method of claim1, wherein receiving a reduced size Mobile IP registration messageincludes receiving the registration message over an air link.
 3. Themethod of claim 2, wherein said reduced size Mobile IP registrationmessage includes a base station identifier identifying said basestation.
 4. The method of claim 2, the method further comprising:storing, prior to receiving said reduced size Mobile IP registrationmessage, state information corresponding to said wireless terminal, saidstate information including at least one of a Home Address, Home AgentAddress, and wireless terminal profile information.
 5. The method ofclaim 4, further comprising, prior to said storing step, receiving saidat least one of a Home Address, Home Agent Address, and wirelessterminal profile information from another node which is different fromsaid wireless terminal.
 6. The method of claim 4, wherein generating atleast one of a Mobile IPv4 and Mobile IPv6 registration message includesgenerating a registration message including a Home Agent Address valuewhich was not included in said reduced size Mobile IP registrationmessage.
 7. The method of claim 6, wherein said generating at least oneof a Mobile IPv4 and Mobile IPv6 registration message further includesincluding a Home Agent Address value, the Home Address value is a storedHome Agent Address value that was received from said additional node. 8.The method of claim 7, wherein the Home Address value is zero when saidstored information corresponding to said wireless terminal does notinclude a non-zero Home Address value.
 9. The method of claim 6, whereinsaid generating at least one of a Mobile IPv4 and Mobile IPv6registration message further includes incorporating a Care-of Address,that identifies said base station, into said generated Mobile IPv4 andMobile IPv6 registration message.
 10. The method of claim 10, whereinsaid reduced size Mobile IP registration message includes a messageidentifier, said message identifier includes at least one of a sequencenumber and a time stamp.
 12. The method of claim 11, wherein saidmessage identifier includes both said sequence number and time stamp.13. The method of claim 5, wherein said other node which is differentthan the wireless terminal node is an authentication and authorizationserver.
 14. The method of claim 5, wherein said other node which isdifferent than the wireless terminal node is another base station towhich said wireless terminal was previously connected to.
 15. A basestation comprising: a receiver module for receiving a reduced sizeMobile IP registration message; a signal generation module forgenerating from said reduced size Mobile IP registration message atleast one of a Mobile IPv4 or Mobile IPv6 registration message.
 16. Thebase station of claim 15, wherein said receiver module is an radioreceiver module for receiving the registration message over an air link.17. The base station of claim 16, further comprising: memory for storingreceived reduced size Mobile IP registration message, said memoryincluding a stored reduced size Mobile IP registration message thatincluding a base station identifier that identifies said base station.18. The base station of claim 16, wherein said memory further includes:state information corresponding to said wireless terminal, said stateinformation including at least one of a Home Address, Home AgentAddress, and wireless terminal profile information.
 19. The base stationof claim 18, further comprising: a network interface for receiving saidat least one of a Home Address, Home Agent Address, and wirelessterminal profile information from another node which is different fromsaid wireless terminal.
 20. The base station of claim 18, wherein saidsignal generation module includes means for accessing said stored stateinformation to retrieve from the stored state information a Home AgentAddress value which was not included in said reduced size Mobile IPregistration message but which is to be included in at least one of aMobile IPv4 or Mobile IPv6 registration message to be generated from areduced size Mobile IP registration message.
 21. The base station ofclaim 20, wherein said signal generation module further includes meansfor obtaining a Home Agent Address value that was received from saidadditional node from stored information for inclusion in said at leastone of a Mobile IPv4 or Mobile IPv6 registration message to begenerated.